Roller device impact clutch



Feb. 19, 1952 w, EMERY 2,586,314

2 SHEETS-SHEET i Feb. 19, 1952 v w, MIEMERY 2,586,314

2 smm a-susm 2 Patented Feb. 19, 1952 ROLLER, DEVICE IMPACT CLUTCH William M. Emery, Summit, N. J., assignor to The Rotor Tool Company, a corporation of Ohio ApplicationFebruary 7, 1945, Serial No. 576,643

2 Claims.

My invention relates to improvements, in impact clutches generally, and more specifically to animpact clutch mechanism which is particularly adapted for use with portable power driven tools, such as employed for rotating or tightening screws or nuts.

An object of my invention is the provision of an impact clutch which is operable by centrifugal force to interlock the clutch parts, and is automatically released when the turning torque of the work piece becomes excessive, and thereafter delivers a series of torque producing impact blows without stalling or materially decreasing the speed of the driver.

Another object of my invention is to provide an improved clutch means for-an impact clutch employing interlocking parts which are automatically released when the turning torque of the work piece becomes excessive, and to provide an air pressure cushion to oppose the releasing action.

Another object of my invention is to provide an improved clutch means for an impact clutch employing interlocking parts which are automatically released when the turning torque of the workpiece becomes excessive, and to provide cam surfaces to oppose thereleasing of the interlocking parts.

Another object of my invention is to provide an impact clutch having any outer driven member and an inner driving member with means responsive to centrifugal force to interlock said driven and driving member, and having impact surfaces on the driven member to contact the centrifugal responsive means and force same out of they interlocking position.

Other objects and a fuller understanding of my invention may be had by referring to the following description and claims, taken in conjunctionwith the accompanying drawing, in

air pressure cushioning behind the clutch balls;

Figure 5 illustrates a modified form of impact surface to contact the balls; and

2 Figure 6. is a fragmentary view of the interconnecting balls in contact with both the driver and driven members.

With reference to the Figure 1, I illustrate a cross-sectional view of a type of impact clutch employing the principles of myinvention. In this embodiment I illustrate a torque transmitting member ll having a power shaft 2'! to -receive rotational power from a suitable driving source. Thepower shaft 21 is illustrated broken off, and may extend to any suitable driving power unit, not part of this invention. Suitable driving power units may include electric, fluid or pneumatic motors or any mechanical means.

A hammer member 1'2, and an anvil member it are held in axial alignment with the torque transmitting member H by means of a longitudinal slidably mounted spindle I-5. An'extension '28 on the spindle I5 is secured within a centrally disposed hole 29- in the torque transmitting member H. A bearing plate H is slidably mounted upon the hammer member I2 and is disposed to carry a bearing 23 to provide bearing surfaces for the torque transmittingmember I l. The bearing 23, which is illustrated as being a ballbearing, is secured to the torque transmitting member and the slidable bearing plate 21. Abutment corners 25- on the torque transmitting member H, and a retainer ring '26 on the bearing plate 2!, serve to secure the bearings 23 to the bearing plate 2! and the transmitting member H in such a manner that the members 21 and H may rotate relative to one another, but are held against longitudinal movement therebetween, and therefore, must move endwise as a unit. A snap ring '22 is provided to limit the movement of the bearing plate: 2! awayfrom the hammer member [-2.

There are two clutch members inthisembodiment of ray-invention. The first clutch member is indicated generally by the reference character 31 and is of the-conventional dog clutch type and operates between the torque transmitting member H and the hammer member l2. The dog clutch 3 comprises teeth ii] on the torque transmitting member H, and teeth M on the hammer member [2, which are normally held apart by a spring is positioned between the members H and [2 by a guide and stop member 19 mounted on. the hammer member l2, and a stop 20 mounted on the torque transmitting member II. The second clutch member is indicated generally by the reference character 32 and is the impact clutch illustrated in cross-section in the Figures 3 or 5., Theclutches 3| and 32 are both illus- 3 trated in their relaxed position, and therefore, the ball 30 on the lower side of the illustration is shown in its outward position because of gravity. The impact clutch 32 is illustrated as comprising apertures 33 in the hammer member i2, impact races 34 on the anvil member ID, and interconnecting clutch balls 30 positioned to interconnect the hammer member I2 and the anvil member ID. The impact races 34 are preferably offset a longitudinal distance in an axial direction from each other, as illustrated in the Figures 1 and 4, in order that each of the balls 30 will operate in only one impact race 34. The apertures 33, in this embodiment of my invention, are provided with a flared portion 35, and the impact races 34 are disposed to provide impact abutment surfaces 36 against which the balls 30 may strike. Although the impact races 34 are offset, they are spaced apart in substantially 180 relationship to each other in order that the balls 30 may strike their respective abutment surfaces 36 at the same time and thereby act as a unit. The Figure illustrates an alternative type of race 34 in which there only is one imy, pact surface provided. The impact surfaces 33 and the flared portion 35 may be varied to suit in into the reduced section l6, whereby the endwise movement of the spindle i5 and consequently the endwise movement of the torque transmitting member H, is limited. The hammer member i2 is bearinged on the spindle IE, but is full floating thereon and is thus free to move in any direction relative to the spindle except as restrained by other influences.

A work engagement part 31 is provided onthe anvil member ill to hold a suitable tool thereon. Although the part 3! is illustrated as a square stud to receive a socket of a tool, it is understood that any suitable work engagement part may be provided in place thereof. In other words, conventional means may be used for attaching thereto suitable drivers for studs, screws and the like which are not part of this invention.

For the purpose of illustrating, assume that the device is to be used to tighten a nut on a stud.

As the operator places pressure upon the shaft 21, the torque transmitting member II is moved into engagement with the hammer member l2 against the urging of the spring I 8 and interlocks the teeth I3 and 14 of the dog clutch 3|. The motor is then started to rotate and torque is delivered through the torque transmitting member H to the hammer member I 2. As the rotational speed of the hammer member 12 increases, cen trifugal force operates to throw the balls 38 outwardly from the center of rotation. As the hammer member 12 rotates, a position will be reached in which the apertures 33 register with the impact races 34, at which time the balls 30 are centrifugally forced to move out and contact the bottom of the races 34. As illustrated in the fragmentary view 6, when the balls 30 are in the described outward position in contact with the bottom of the races 34, the flared portions 35 of the apertures 33 are in contact with the balls 30 and tend to cam the balls 30 outwardly from the center of rotation of the hammer member [2, and therefore supplements the action of the centrifugal force. As the rotating hammer member l2 carries the balls along the impact races 34 in the position described, the balls 33 are in position to contact the impact abutment surfaces 36 at the end of the races 34. This position of impact is illustrated in the Figure 6. In the Figure 6, it will be noted that two opposing camming actions tend to operate at the moment of impact between the balls 33 and the abutment surface 36. The camming action by the flared surfaces 35 has been described, and a similar camming action is produced between the abutment surfaces 36 and the balls 33 at the moment of impact. Of course, centrifugal force is also opposing the cammin action produced between the surfaces 36 and the balls 30. It is understood however, that the abutment surfaces 36 and the flared portions 35 must be so constructed that the camming action between the abutment surfaces 35 and the ball 30 will be somewhat larger than the combined forces of the camming action of the flared portions 35 in conjunction with the balls 33 and the centrifugal force.

As the nut first starts on the stud, there is very little resistance to it progress. Therefore, the described centrifugal force and the camming action of the flared portion 35 will hold the balls 33 in the races 34 and in contact with the abutment surfaces 38, and thereby cause the anvil member Hi to rotate and deliver full speed rotation to the work engagement part 31. As the nut meets opposition to its free rotation, such as by the nut seating in place or by moving over tight threads, or by any other opposition, the work engagement part 37 and the anvil member H! tends to slow down and rotate at a slower speed than that of the hammer member i2. However, the balls 38 will stay in their outward position until the camming action between the abutment surfaces 36 and the balls 3!] is large enough to oppose the combine-d force of the camming action of the flared portions 35 and the balls 3! and the described centrifugal forces. As soon as the camming action between the abutment surfaces 36 and the balls 33 is sufficiently large to move the balls 30 back into the apertures 33, the hammer member I2 is free to rotate within the anvil mem her In. Thereafter, the balls will be repeatedly thrown out and driven back under considerable opposition as described. Because of this opposition, a momentarily large torque is produced in the anv l Ill which is transmitted to the Work engagement part 31. It may not be desirable to produce a torque impact upon every revolution of the hammer member 12, therefore, by selecting balls 30 of a suitable size and weight, and by proper arrangement of the abutment surfaces 36 and the flared portions 35, the number of revolutions which the hammer member i2 will make before the balls 33 are again thrown outwardly into the races 34, may be controlled.

With reference to the Figure 4, I illustrate an alternative type of impact clutch embodying the features of my invention. This embodiment, however, employs only one clutch member, and in addition thereto, provides for live air pressure to supplement the action of the centrifugal force and tends to hold the balls 30 in engagement with the impact races 34 of the anvil. As illustrated, the hammer member I 2 is onesolid piece and extends to the driving power'unit through the power shaft 21. The hammer member I2 is longitudinally slidably mounted relative to, and inside, the anvil member III. A spring member 40 is positioned within an end cavity 4| of the anvil member ID and contacts the hammer member iii to urge the hammer member l2 longitudinally endwise, and thus move the apertures 33 out of alignment with their respective impact races 34. This illustration shows the hammer member 12 as it would appear when pressed inwardly against the action of the spring 49 and in position for operation.

Also, I illustrate a method of delivering air under pressure to the apertures 33 to supplement the centrifugal force action of the balls 39. Whenever air is used, the apertures 33 are preferably made with straight side walls instead of being provided with a flared portion as illustrated by the reference character 35 in Figure 1. The live air pressure from pneumatic motors may be employed for this purpose, if a pneumatic motor is used as a source of power. The air is delivered to the apertures 33 by means of a main artery 38 extending longitudinally within the power shaft 21 and the hammer member I2. Branch ducts 39 extend from the main artery 38 to the apertures 33.

In operation, this embodiment of my invention will permit the hammer member to rotate freely within the anvil member [0 whenever the hammer member I2 is moved longitudinally rearwardly with respect to the anvil member In. To begin operation, the operator places pressure upon the shaft 21, and thereby moves the hammer member I2 into the position illustrated in the Figure 4. The motor is then started to rotate, and as the rotational speed of the hammer member l2 increases, centrifugal force plus air pressure operates to throw the balls 30 outwardly from the center of rotation. The operations of the balls 38 between the races 34 and the apertures 33 then are exactly as described in connection with the embodiment illustrated in the Figure 1. However, instead of a flared portion 35 to supplement the centrifugal force, the live air pressure that is supplied to the ducts 38 and 39 provide a cushion and active force behind the balls 30. Thus, in order to force the balls 30 back within the apertures 33, the camming action between the surfaces 36 and the balls 30 must be sufficiently large to overcome the combined action of the centrifugal force and the air pressure.

Whenever the impact clutch is to be disengaged from the work piece, the operator removes the pressure exerted on the shaft 21 and thereby permits the spring 40 to urge the hammer member l2 rearwardly and,thus move the apertures 33 and the balls 30 out of position to contact the impact races 34. Any further rotation of the driving unit and the hammer member l2, of course, will not cause rotation of the anvil member 10.

It is pointed out, that although most impact 1;

by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

I claim as my invention:

In an intermittent rotary impact clutch, the combination of a revolvable hammer member having walls defining a bore, an anvil member having at least an abutment in alignment with the said bore, an intermediate ball member inserted in said bore for movement under centrifugal forces therein to engage said abutment when the hammer member revolves, means to direct air under pressure into said bore behind said intermediate ball member to supplement said centrifugal forces.

2. In an intermittent rotary impact clutch, the combination of a rotating hammer member having walls defining at least a first and a second bore, said bores being longitudinall spaced in an axial direction from one another, an anvil member having an abutment to correspond to each said bore, said rotating member and said anvil member being shiftable relative to one another in a first position of driving engagement and a second position of free turning to alternately place the bores and their corresponding abutments in cooperating alignment with one another when in the said first position, and to remove the bores and their correspondihg abutments from cooperating alignment when in the said second position, and an intermediate member inserted in each said bore for movement under centrifugal forces therein to engage said corresponding abutments when the rotating member and anvil are in the said first position and the hammer member revolves, whereby driving force may be applied to and removed from the anvil member at the will of the operator by shifting the members relative to one another to their first and second relative positions.

WILLIAM M. EMERY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 924,749 Drapiec June 15, 1909 1,496,577 Klausmeyer June 3, 1924 1,567,912 Carey Dec. 29, 1925 1,703,061 Coleman Feb. 19, 1929 1,874,658 Tschudi Aug. 30, 1932 2,132,631 Jones Oct. 11, 1938 2,178,657 'Travnicek Nov. 7, 1939 2,342,540 Hale Feb. 22, 1944 2,439,337 Forse Apr. 6, 1948 2,439,823 Porter Apr. 20, 1948 FOREIGN PATENTS Number Country Date 318,623 Great Britain Dec. 3, 1930 431,875 Great Britain July 17, 1935 559,894 France June 26, 1923 580,209 France Aug. 25, 1924 656,826 France Jan. 5, 1929 

